Gas mask facepiece



May 21 1,940- R. MoNRo ET AL l 2,201,198

Filed Feb. 24, v19:58 2 sheetsfsneet 1 Pmed.le:21,1940I GAs MASK FACEPIECEV Randolph Munro, Edgewood Arsenal, Armand V. Motsinger, Aberdeen, Herbert A. Scruton, Baltimore, and Glenn A. Little, Edgewood Arsenal,

Application February 24, 193s, serial No; 192,316

A sfclaims. (ci. 12s-141) l (Granted under the act of March `3, 1883, as U lfa'mended April 30, 1928; 370 0. G. 757) i The invention described-,herein may bemannfactured and used by `or for the Government for 4governmental purposes,` without the payment to kus ofany royalty thereon# J This v invention relates to at new and improved gas mask facepiecewhich isflight inlweight'and comfortable t Wear. ,1' i A, In order to prevent the. passageof harmful vaporsfory gases through the gas mask facepiece, it has heretofore been common practice to' fabricate; these facepiecesof heavy material such as rubber,rubberized cloth, ork other fabrics rendered highlyimpermeable .to harmfull agents. Relatively thick lenses havebeen securedto these Afacepieces such` as `glass lenses j secured by metal binding rings.` vWhile suchv facepieces have been vsuccessful in inhibiting penetration of harmful agents, they are expensive to manufacture and vare Yvery uncomfortable to' wear due to their weight. 1 A

One object ofthisrinvention is to provide a gas vmask facepiece which is vhighly impermeable to harmful gases andvapors and yet is 'simple and cheap to manufacture and is very light in weight.

Another object of the invention is to provide av gas mask facepiece having lenses curved .to the facial contour, thus materially kincreasing the range of vision, -the lenses being readily secured in placewhen the facepiece is made.

Another object of the invention is to provide a facepiece fabricatedv from plied materials permanently united together, with lenses secured' in place between the plied materials.

, Another object of the invention is to provide a Y both will readily vweldthe materials together.

-v Another `object of thistinventionis to provide afacepiece having-eye lenses, faceblank, and cement containing compatible materials so' that the leye lenses will weld tothe faceblank material.

yAnother object of ,this inventiorris to, provide a facepiece having eye lenses vand fa'ceblank made of thermoplastic materials and such `that the two rmaterials will weld when heat and pressure are applied'. v-

,.y These and variouspthenobjects of this invention will be apparent .from` the following description and claims. with the understanding that the liied chin seam.

inventionl is not limitedto the precise details herein given. l

In the drawings: v v .Figures 1 and 2 arefront'and sideelevations of the complete facepiece of a gas mask.

thecurvature of the eye lenses.

Figure 6 isla section 6 6 of Figure-2 showingthe chin seam, l t

JFigure 'I is asimilar section showing a modi- Figures 8, 9, 10, 11, 12, and 13` are sections B-l of Figure` 4 showing modified lens mountings.

Figure 14 isan enlarged section of the facepiece materials separated.

.bined with a layer of materialhighly impermeable to gases and vapors. lThe impermeable layer may be thermoplastic. It may be a gas-resistant material such as viscose fabric, drying oil composition, cellulose nitrate, cellulose acetate, or sheeted regenerated cellulose. Eye lenses made of cellulose acetate, cellulose nitrate or similar clear materials maybe insertedas hereinafter described. o v g In the preferred form' of this invention. the layers of stronger material areplaced on each Iside of the thin sheet of highly impermeable material. The stronger materials maybe cotton cloth, thin leather vor leather substitutes, or other fibrous materials having the requisite mechanical strengthand flexibility.

Preferably the outermaterialsl are coated on their inner surfaces with a coating of such nature withthe impermeable inner-fsheetby the application of solvents, cement orlheatand pressure," to thus form in effect a unitarysheet. For example,

vexcellent results have been obtained `by coating cotton cloth of the outer ply I, Figure 14, with cellulose acetate composition, or byusing a commercial coated fabric having a cellulose acetate composition coating, then placing a thin sheet of cellulose acetate 2 between two sheets of the coated cotton cloth outer ply I, with thecoated sides facing inwardly, the coated sides being cov- PATl-:Nr OFFICE s 'that a strong permanentsea-l` may beobtained 2 ered with a mutable adhesive which win 'readily combine and form a permanent seal with the coating and cellulose acetate inner sheet 2f, then uniting the plies by passing through rolls under pressure and allowing the cement to dry through the outer layers. It is not necessary in all cases to coat the cloth of the outer ply I, Figure 14, with the' cellulose acetate composition, butthe adhesve may be applied directly to the cloth and the assembly otherwise made as above. The

number of plies of material used, thematerial selected, and arrangement of plies depends on the length of time the facepiece is to resist `the A penetration of gases.

It will be understood that the? cement used should be selected in accordance with the particular impermeable sheet, lenses, and coatings used. The adhesive for celluloseacetate lenses, inner sheet and composition coating, for example, may contain cellulose acetate and an alkyl resin (a combined gum and plasticizer) equal parts, dislenses and cellulose nitrate coated fabrics have been used by this process to make faceblanks.

When materials are/used that become adhesive l by the application of a solvent the solvent may be usedl without' additional cement and the material may be plied by the application of the solvent and pressure. An example of such materials are cellulose nitrate lenses and cellulose nitrate coated fabrics. l

The highly impermeable ply of material is preferably adhered to one ofthe two outer 4plies before the outer plies are died out for assembly. The outer plies then have holes cut out for lens and are adhered together with lens in place over the holes. The outer plies are adhered together and to the lenses by means of .either the thermoplastic, solvent,` or Acement method described above. After this operation the plied material is cut to the proper shape so that the facepiece can be shaped to fit the face by a single seam along the chin portion, an opening left in front of the wearers mouth and nose for attachment of an angle tube. The general shape ofthe outer material prior to assembly is shown and described in U. S. patent to R. Monro, #1,395,759, dated November 1, 1921, but modified so that the angletube may be placedand shaped to reinforce and hold the front vof the` facepiece to the desired rIn certain types of facepeces the impermeable inner sheet 2 does not have openings cut therein for the lenses, since this material, l. e., cellulose acetate, cellulose nitrate, or regenerated cellulose sheet, when) assembled with the two outer sheets, may form. the lenses. II of the completed facepiece. By this one-piece construction of lenses II and inner sheet 2 there is no possibility of leak- Vage between the facepiece and the lenses, as is the casewith separately attached lenses, and the facepiece may be lighter in weight due to the thin inner sheet being used toform the eyel lenses.

. After the plies are firmly bondedtogether with eye lenses in place and the blank so 'formed cut y tothe proper shape as described, the` facepiece is then completed by drawing the chin seam portions 3 (Figure 6) together to form the chin seam.

Preferably the chin seam issewed and adhesive strips 4 (Figure 6) are placed along the inner and outer faces of the seam. These strips are coated with suitable compounds to permit adhesionV to the faceblank by the applicationA of solvents and pressure, or heat and pressure. Inan alternate method twoside portions 5 (Figure 7) are brought intov surfacecontct and sewed together. Then the facepiece is opened to thus form a U-shaped `groove which is lled with a suitable plastic 6 such as highly plasticized cellulose nitrate composition dissolved in suitable solvents.

ReferringftoFigures 1, 2, 3 and 4 it will be seen that .the front. of the mask makesa straight line from the forehead over the nose of the wearer. The top of the pressed metal angletube is at the lower end of this line and the depth is such that the exhalatin port I is just in front of the mouth fondrainage through this port and the flutter valve 8 of any moisture collecting inside the facepiece. The angletube body 9 is of such a shape to prevent distortion of the faceblank material `in the frontuof the facepiece. It is secured by means of. a clampover the faceblank material in the opening provided for it in the facepiece. ,A de'ector I0 is also shapedto hold the facepiece in the desired shape and to t the inside curvature of the facepiece dueto the eye lenses being curved. Air from a canister (not shown) enters the facepiece through the inlet tube I2 di rectly to .the 4space I5 -between the deiiector II and faceblank I3near the eye lenses II. The top of the ,deflectoris madenarrow near the lenses II to forman entrance for the incoming air to pass .over andclear thelenses II. The bottom of v.the deflector isattached, lfor example `by soldering, to thegangletube justk above the outlet port 1, and below the inlet tube I 2. The top of the deiiector is secured to the faceblank by` means of a capped rivet I4. The inlet stem I2 preferably is turned to one side for an air hose and canister (not shown). The inlet stem I2 attachedto the Il are placed directly above the centers of curva-` ture of the lenses Il. Due to thek curvature of the lenses, there is a tendency of the facepieces to bulge at'the periphery above the lenses. By placing the upper rivets at these points of bulging, a tight t of the mask is secured.

The eye lenses are large in order to provide good vision. They are curved as shown in Figure 5 to provide a good t of the facepiece and maximum side vision.

Figures 6 and 7 sho disclosed. y l v Figure 8 shows a method of securing a lens 20 made of cellulose acetate or` similar material over the hole cutin a. single layer of faceblank material I. This material may beacellulose acetate composition coated fabricI as described above. The lens is adhered preferably to the coated side by a cement, solvent, or heat and pressure as above disclosed. Y

Figure 9 shows a lens 2| secured between two layers of coated fabric I, which are plied, prefer ably, with coated surfaces facing the lens and adhered as above disclosed.-

` ,the chin seamL as above Figure 10 shows a lens 22 secured between plies as in Figure 9, except that the thin highly impermeable sheet such as cellulose acetate is fabri.

cated between the outer plies to increase the degree of gas protection.

Figure 11 shows an eye lens 23v formed by the thin impermeable sheet 2 extending over the holes in the faceblank material I.

Figure 12 shows a cellulose acetate lens 24 adhered to the outside 'of two plies of faceblank material I by one of the methods as above disclosed.

Figure 13 shows a cellulose acetate eye lens 25 out to it in the hold in the plied faceblank ma-v terial I. It is secured in place by molding plasticized cellulose acetate rings on either side of the lens-faceblank joint. Eye lenses have been secured in this manner by applying a cement as above disclosed, then molding the rings over the joint by la themoplastic process.

to secure additional strength, it is sometimes preferable to sew the lenses in place after cementing. The stitches are passed through the overlapped'edges of fabric and lenses and the small holes are then covered with a plastic cement.

The gas mask facepiece of this invention is very light in weight, is simply and cheaply made, and provides a wide angle of vision both verticallyand horizontally. It is made for a substantially universal t, that is, so that it will fit a large majority of adult faces, the arrangement of the attachment straps being such as to secure a gastight fit on most adult faces.

In the following claims the word fabric is intended to include cotton cloth, leather or.

imitation leather,l or other brous sheet material of requisite strength and thickness.

It will be understood that the invention is not limited to the details of construction herein set forth by way of illustration, since changes and variations may be made therein by those skilled'in the art without departing from the spirit of the invention nor exceeding the scope of the claims.

` We claim:

1. 'I'he method oi makinggas mask facepieces -which comprises coating a'fabric with cellulose nitrate composition, assembling two sheets lof the coated fabric on opposite sides of a sheet of cellulose acetate with the coated sides of the fabric contactingsaid sheet, permanently uniting the assembly by the application of heat and pressure, cutting the lens openings in the assembled sheets, placing lenses of relatively still cellulose acetate over said openings, sewing the lenses in place, and securing and sealing two edges of the assembly to form a ohinseam for the facepiece.

2. The method of making gas mask facepieces which comprises coating a fabric with a layer of a material of the group consisting of cellulose nitrate, cellulose acetate and sheeted regenerated cellulose, assembling two sheets of the coated fabric on opposite `sides of a gas impervious sheet of same material as vthe coating `on the i'abricl Referringto Figures 8, 9, 10, and 12, in order with the coated sides of the fabricl facingA the sheet, subjecting this assembly simultaneously to heat and pressure to firmly unite the assembly,

cutting the assembled fabrics and 'sheet to desired shape with two openings for eye-lenses, and securing and sealing over said eye openings lenses 'of the same material as the coating. l

3. The invention as deilned in claim 2 wherein said lenses are thicker than said sheet, but are sufficiently flexible to conform to curvature of Y the face.

RANDOLPH MONRO.l HERBERT A. SCRUTON.

GLENN A. LIITLE. ARMAND V. MOTSINGER. 

